The field of the disclosure relates generally to components having an internal passage defined therein, and more particularly to forming such components having the internal passage lined with a coating.
Some components require an internal passage to be defined therein, for example, in order to perform an intended function. For example, but not by way of limitation, some components, such as hot gas path components of gas turbines, are subjected to high temperatures. At least some such components have internal passages defined therein to receive a flow of a cooling fluid, such that the components are better able to withstand the high temperatures. For another example, but not by way of limitation, some components are subjected to friction at an interface with another component. At least some such components have internal passages defined therein to receive a flow of a lubricant to facilitate reducing the friction.
At least some known components having an internal passage defined therein exhibit improved performance of the intended function after a coating is applied to an interior wall that defines the internal passage. For example, but not by way of limitation, some such components are subjected to oxidizing and/or corrosive environments, and oxidation and/or corrosion of the interior wall unfavorably alters flow characteristics of the internal passage. For at least some such components, a coating on the interior wall to inhibit oxidation and/or corrosion improves a performance and/or a useful operating lifespan of the component. However, such coatings can be difficult or cost-prohibitive to apply completely and/or evenly to certain internal passageways, such as, but not limited to, internal passageways characterized by a high degree of nonlinearity, a complex cross-section, and/or a large length-to-diameter ratio.